REVIEWS 151 



portance to our conceptions of the process of heredity, and no person more 

 fitted than Professor Morgan could have been found to deal with the subject. 

 The zoologists and botanists of the English-speaking world are under a debt 

 of gratitude to the author for the successful way in which he has performed 

 his task of condensing this mass of material and presenting it in a compre- 

 hensive way within reasonable limits. 



The book, as the reader is informed on the cover is intended as " A college 

 text for use in courses in genetics presenting the fundamental aspects of 

 heredity from the latest developments in the field of biology." Few biologists 

 could be found competent to criticise the subject-matter of this volume, and 

 for ourselves we are content to express our gratitude for having such a multi- 

 tude of facts presented within so small a compass and with such a wealth of 

 illustration . On the other hand, however, its very catholicity has necessitated 

 a briefness of treatment and terseness of statement that makes it difficult to 

 read. For persons like the general reader and the student, who are not 

 thoroughly conversant with the complex terminology employed, it is hard 

 work to follow the arguments presented. Technical terms are used freely, 

 sometimes with inadequate explanation and sometimes with none at all, 

 and again when, in the opinion of the reviewer, they are unnecessary since 

 they are irrelevant to matter in hand. Again, we find statements of deduc- 

 tions put in brief form as if they were obvious truisms, whereas they are only 

 obvious to those familiar with the work. It must indeed be difi&cult for the 

 specialist to realise the ignorance of the ordinary reader on details of his own 

 particular line of work, and we fear that Professor Morgan has not taken this 

 factor sufficiently into account in his treatment of the subject. 



On p. 63 about two- thirds of the way down in an annoying printer's error — 

 the duplication of a line to the exclusion of another ; and in the second line of 

 the table given at the bottom of p. 76 the figures in the end column appear 

 to have been reversed. We also note that in the literature list O is placed 

 after P and that several recent papers referred to in the text are omitted. 



These are comparatively trivial matters, however, and we wish to empha- 

 sise the excellence of this book and its indispensability to all who wish to make 

 themselves acquainted with the striking advances that have been made in 

 the cytological study of heredity during the past few years. 



C. H. O'D. 



Inbreeding and Outbreeding. Their Genetic and Sociological Significance. 



By E. M. East, Ph.D., and D. E. Jones, Sc.D. [Pp. 285 with 46 

 figures. Monographs on Experimental Biology.] (Philadelphia and 

 London : J. B. Lippincott & Co., 1919. Price $2.50 net.) 



This volume deals with the question of Inbreeding and Outbreeding mainly 

 from the point of view of the horticulturist, although certain examples are 

 chosen from the animal kingdom and the general bearing of these interesting 

 problems discussed. The last chapter, about 20 pages, treats briefly of certain 

 aspects of the matter as it is or may be applied to man, more especially in 

 connection with the mixture of races. The book is particularly useful where 

 it deals with the application of pure line selection to the breeding of Indian 

 corn and the increasing vigour that results from heterosis, subjects in which 

 the authors have done a great deal of research. 



When we read such statements as " Galton measured the inheritance of 

 groups of individuals to their progenitors and failed [sic] because his method 

 could not take into account the true relationship between the germinal 

 constitution and the body characters of an individual," we feel that the 

 outlook of the work is somewhat limited. Indeed the authors' own attitude 

 could almost be summed up in a phrase used in connection with the vari- 

 ability in sexual and asexual reproduction, " He is left with only one reasonable 



